The objective is to conduct a case-control study of congenital heart disease, to evaluate the possible teratogenic effect of several drugs reported in previous studies to be associated with congenital heart disease. The drugs to be evaluated are ampicillin, aspirin, Bendectin (R), chlordiazopoxide, codeine, diazepam, phenobaribital, phenothiazine, and tetracycline. Cases will include all infants born in Massachusetts during 1980-82 with serious congenital heart disease, ascertained either through the New England Regional Infant Cardiac Program or through death records of the Massachusetts Division of Vital Statistics. Controls will be a random sample of all births to Massachusetts residents during the study period. Exposure information will be obtained through telephone interviews, pre-natal records and pharmacy records. The data will be examined for associations of drug exposure with the overall frequency of congenital heart disease and with specific defects. Odds ratios will be estimated using either a contingency table approach or, if necessary, multivariate techniques.